where could find a good web site that would show me how to write a negative message to my boss

Question

Depending on the type of negative message you want to write microsoft has several templates available that can be used, and ammended to fit your needs.

This depends on what you mean by a "negative message." If you want to propose a change that the boss might not want initially, It is best to start your message with some positive points before you begin the "negative" aspects.

Here are some sites discussing persuasion and influencing others.

http://www.members.cox.net/dagershaw/lol/InfluenceAntecedents.html
http://www.members.cox.net/dagershaw/lol/InfluenceMorePrinciples.html
http://www.members.cox.net/dagershaw/lol/InfluenceStillMore.html

I hope this helps. Thanks for asking.